[Xen-changelog] [xen stable-4.6] x86/MSI: handle both MSI-X and MSI in cfg space write intercept

[patchbot@xxxxxxx]

commit bc2b1bef1129f4219bc384f5ee2ef6d1bdcb86e3
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Mon May 9 12:54:27 2016 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon May 9 12:54:27 2016 +0200

    x86/MSI: handle both MSI-X and MSI in cfg space write intercept
    
    In commit aa7c1fdf9d ("x86/MSI: properly track guest masking requests")
    I neglected to consider devices allowing for both MSI and MSI-X to be
    used (not at the same time of course): The MSI-X part of the intercept
    logic needs to fall through to the MSI one when the access is outside
    the MSI-X capability bounds.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    master commit: 02eb000e0723470e795725d515d0797be8ca30fd
    master date: 2016-04-25 14:21:13 +0200
---
 xen/arch/x86/msi.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/xen/arch/x86/msi.c b/xen/arch/x86/msi.c
index 3dbb84d..3b4a23f 100644
--- a/xen/arch/x86/msi.c
+++ b/xen/arch/x86/msi.c
@@ -1292,17 +1292,17 @@ int pci_msi_conf_write_intercept(struct pci_dev *pdev, 
unsigned int reg,
                                           PCI_CAP_ID_MSIX);
         ASSERT(pos);
 
-        if ( reg < pos || reg >= msix_pba_offset_reg(pos) + 4 )
-            return 0;
-
-        if ( reg != msix_control_reg(pos) || size != 2 )
-            return -EACCES;
+        if ( reg >= pos && reg < msix_pba_offset_reg(pos) + 4 )
+        {
+            if ( reg != msix_control_reg(pos) || size != 2 )
+                return -EACCES;
 
-        pdev->msix->guest_maskall = !!(*data & PCI_MSIX_FLAGS_MASKALL);
-        if ( pdev->msix->host_maskall )
-            *data |= PCI_MSIX_FLAGS_MASKALL;
+            pdev->msix->guest_maskall = !!(*data & PCI_MSIX_FLAGS_MASKALL);
+            if ( pdev->msix->host_maskall )
+                *data |= PCI_MSIX_FLAGS_MASKALL;
 
-        return 1;
+            return 1;
+        }
     }
 
     entry = find_msi_entry(pdev, -1, PCI_CAP_ID_MSI);
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.6

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